Father thirty years older — Aptitude Question
Father thirty years older: A father is 30 years older than his son. In 12 years the father will be three times as… Answer and worked solution on CodeKairo.
- Topic: Problems on Ages
- Section: Quantitative Aptitude
- Difficulty: Medium
- Time target: 75 seconds
Question
A father is 30 years older than his son. In 12 years the father will be three times as old as his son. What is the son's present age?
Options
- 3
- 4
- 5
- 6
Show the answer and the worked solution
Correct answer: A. 3
Worked solution
- s + 42 = 3(s + 12) = 3s + 36 → 2s = 6 → s = 3.
- Check: in 12 years, 45 and 15. ✓
Answer: 3.
The idea
Small answers are common in this chapter and feel wrong, but the check settles it. Always verify rather than distrust the algebra.
Shortcut. In 12 years the father is three times the son, so the fixed 30-year gap is two parts: the son will be 15 then, so he is 3 now.
Common trap. 6 comes from stopping at 2s = 6 in s + 42 = 3s + 36 and forgetting to halve it; a son of 6 would be 18 against 48 in 12 years, not a third.